This invention relates to a new and improved iontophoretic bioelectrode structure which is simple in design, and to a method of manufacturing the structure.
Iontophoresis is a technique of delivering ions into a person's skin or tissue by placing a solution or other medium containing the ions in contact with the skin, and applying electric current to the medium. The solution or medium containing the ions is typically carried by a first bioelectrode pouch or receptacle. Ions are caused to migrate from the ion carrying medium through the skin or tissue by the application of the electric current to the medium, and by placement against the skin and of a second bioelectrode within proximity of the first bioelectrode and the application of current of opposite polarity to the second bioelectrode. This technique has been discussed in a number of prior art patents including U.S. Pat. Nos. 4,141,359 and 4,166,457. Examples of bioelectrodes which are generally useful for making electrical contact with the skin are described in U.S. Pat. Nos. 3,862,633, 3,945,384 and 3,973,557.
There have been several bioelectrode proposals for carrying the ion solution or medium and placing it in proximity with the skin including provision of a receptacle with a wetable barrier on one side thereof. The wetable barrier or wall is covered until time of use and then uncovered for placement against the skin. Then, upon application of the electrical current, the ions migrate through the wall into the skin.
Another proposed arrangement involves the use of a receptacle having a microporous membrane on one side thereof which may be placed in contact with a person's skin. The membrane is selected so that it will not leak prior to use, but will allow migration of ions therethrough to the skin upon application of an electric current to the ion-carrying solution. With this arrangement, less care need be given to storage, transport, or use of the receptacle since the ion containing fluid will not leak as it is used.
Still another suggested arrangement involves a bio-electrode structure which includes a holder for holding ions to be delivered, wherein the holder is adapted to inhibit movement of ions in a direction generally parallel to the surface of the skin or tissue while allowing movement toward the skin or tissue. One exemplary configuration of this bioelectrode is to provide the receptacle with a gel material preloaded with ions.
Generally, bioelectrodes heretofore proposed either provide for including the ion-containing solution in the bioelectrode as it is manufactured, or simply providing a structure into which ion-containing solution can later be introduced by the user. In the latter case, typically a special structure is provided on the bioelectrode for receiving a solution applicator, and a special applicator structure is provided for supplying the solution to the bioelectrode. Such special structure is employed, among other things, to enable introduction of solution into the bioelectrode without puncturing it.